Jakub Ouhrabka <jouh8664(at)ss1000(dot)ms(dot)mff(dot)cuni(dot)cz> writes:
> I've found this message in my server log:
> ERROR: syscache lookup for index 245488730 failed
Grepping the sources says that the only occurrence of that error string
is in pg_get_indexdef(). I think you must have been doing
pg_get_indexdef() on an index that just got dropped; perhaps someone
was selecting from the pg_indexes view while tables were being modified?
regards, tom lane